1. Field of the Invention
The invention relates to a 3.5 mm audio plug with built-in lighting source, particularly to a built-in light-emitting element with only light-emitting hole exposed out of an audio jack for saving space and easily carrying.
2. Description of the Related Art
With the rapid development of computer and communications technology, electronic products have become increasingly popular; especially mobile phones have become one of the essential devices of modern people. At the same time, the industry continues to introduce new mobile phones with various functions for enhancing the convenience and practicality of mobile phones. For example, smart phones have become the market mainstream, and the all-inclusive applications won the love of consumers.
Laser pens are required for business people and teachers while making a presentation or teaching. However, some laser pens need a mouse or adjust key for projection function so that it is inconvenience to carry all the things for a presentation or teaching.
With the references to FIGS. 1A and 1B, a multifunction laser pen 90 can be inserted into an audio jack 60 of a mobile phone 70. However, the laser pen 90 is exposed out of the audio jack 60 at least 4 to 5 cm when using the conventional laser pen 90; hence, it is inconvenient to carry and requires more space for storing. Moreover, when inserting the conventional laser pen 90 into the audio jack 60, a plug 80 is separated into a first conductive portion 81, a second conductive portion 82, a third conductive portion 83 and a fourth conductive portion 84 by a first insulating layer 85, a second insulating layer 86 and a third insulating layer 87 and the first, second, third and fourth conductive portion 81, 82, 83, 84 are electronically connected to a first terminal 61, a second terminal 62, a third terminal 63 and a fourth terminal 64 in a inserted hole 60; such that, a sound of the mobile phone 70 cannot be outputted by a speaker 71. Therefore, there is room for improvement.